In recent years, cyclosporin is in use for suppressing rejection developed in transplanting organs. Inclusive of the compounds currently under development, the so-called immunosuppressants are expected to be useful as therapeutic agents for articular rheumatism and so on. Said cyclosporin, however, also poses problems of side effects such as renal disorders.
Meanwhile, Japanese Patent Unexamined Publication No. 104087/1989 discloses that an immunosuppressive substance is obtained from a liquid culture of Isaria sinclairii and said substance has been confirmed to be (2S,3R,4R)-(E)-2-amino-3,4-dihydroxy-2-hydroxymethyl-14-oxoicosa-6-enoic acid of the formula ##STR2## disclosed in U.S. Pat. No. 3928572. In addition, Japanese Patent Unexamined Publication No. 128347/1991 states that a series of said compound has an immunosuppressive action.
Referring to Merck Index, 11th edition, it is described that 2-amino-2-methyl-1,3-propanediol (Index No. 460), 2-amino-2-ethyl-1,3-propanediol (Index No. 451) and 2-amino-2-hydroxymethyl-1,3-propanediol (also called tromethamine, Index No. 9684) can be used as surfactants, intermediates for pharmaceuticals, emulsifiers or gas adsorbents and that tromethamine is medically usable as an alkalization agent. In Japanese Patent Unexamined Publication No. 416/1987, a hair dye containing 2-amino-2-(C1-C5 alkyl)-1,3-propanediol is disclosed. U.S. Pat. No. 4,910,218 and J. Med. Chem., vol. 33, 2385-2393 (1990) teach 2-amino-2-(methyl or ethyl)-1,3-propanediol as an intermediate for an antitumor agent. Also, Japanese Patent Unexamined Publication No. 192962/1984 teaches that the aforementioned 2-amino-2-(C1-C5 alkyl)-1,3-propanediol or 2-amino-1,3-propanediol can be used as a stabilizer for an antigen or antibody-sensitized latex reagent. Moreover, U.S. Pat. No. 3,062,839 teaches 2-methyl- or ethyl-amino-2-(furylmethyl, phenylmethyl or phenylmethyl substituted by lower alkyl, lower alkoxy, chloro, hydroxy or unsubstituted amine)-1,3-propanediol having a tranquilizer action and J. Org. Chem., vol. 25, 2057-2059 (1960) teaches 2-methylamino-2-(phenylmethyl or phenylmethyl substituted by 2-methyl, 3-methyl, 4-methyl, 4-methoxy or 4-hydroxy)-1,3-propanediol. It is not known, however, that these compounds have immunosuppressive actions such as suppression of rejection developed in organ transplantation, prevention and treatment of autoimmune diseases and the like.
An object of the present invention is to provide novel 2-amino-1,3-propanediol compounds having superior immunosuppressive action with less side effects.